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Research

Overview

Our department and faculty are committed to research in ophthalmology to enhance our understanding of ocular disorders and identify new targets for therapeutic intervention. We not only actively participate in major national clinical trials but also focus on basic science and related translational research. The excellent collaborative effort between our clinical research faculty, fellows, residents and research faculty makes the environment most conducive for research in the department.

To achieve this aim, there are close interactions between the basic science researchers and the clinicians on a regular basis. Formal scheduled meetings are held four times a week from 8 a.m. to 9 p.m. where clinicians and the researchers present, discuss and exchange ideas about current challenges in ophthalmology. These meetings take place in the form of M & M’s, grand rounds, research administrative meetings, case presentations and clinical and basic science journal club presentations. The basic science journal club that takes place every Friday provides an opportunity for the basic science researchers to educate and inform the residents, fellows and the faculty regarding new developments relevant to clinical practice of the future. This time is also utilized for educating the clinicians about the relevant concepts of molecular and cell biology, with special emphasis on neurobiology.

The research laboratory provides a unique opportunity to the resident and fellows as well as faculty members at the department of ophthalmology to formulate and answer clinically relevant questions and to gain an insight into the pathophysiology of ocular diseases and a better understanding of current and experimental treatments. The laboratory is located within the premises of the clinical facilities allowing easy access to the clinicians to the laboratory facilities and expertise.

On the other hand close interaction of basic science researchers and the clinicians provides insight to the researchers to develop clinically relevant basic science research programs.

Clinical Research

Our department actively participates in a number of NIH and industry-sponsored clinical trials, with major emphasis on trials related to retinal diseases. In addition, we have several ongoing IRB approved clinical trials within the department and in collaboration with other departments that are relevant to everyday clinical practice. There is lot of emphasis on being at the forefront of technological advances made in the field of diagnostic ocular imaging. As a result of our commitment, we have been recognized as a major site for developing clinical applications of advanced imaging modalities by industry leaders such as Heidelberg Engineering, Zeiss Inc. and Volk Opticals.

NIH sponsored clinical trials

Diabetic Retinopathy Clinical Research (DRCR):
The DRCR Network is a collaborative network funded by National Eye Institute (NEI), dedicated to facilitating multicenter clinical research of diabetic retinopathy, diabetic macular edema and associated conditions.

Website: http://drcrnet.jaeb.org/ViewPage.aspx?PageName=Home_Page
Principal Investigator: K.V.Chalam, M.D., Ph.D.
Co-Investigators: Sandeep Grover, M.D., Shailesh Gupta, M.D.

We joined the DRCR network in the year 2007 and to date, we have over 175 patients enrolled and actively participating in the various study protocols. In the year 2009, we were recognized as the top performing clinical site out of the 200 certified sites in the DRCR network. Dr. Chalam, who is the Chairman of the department also serves as one of the members on the DRCR Executive Committee. The DRCR protocols we are actively involved in are as follows:

  • Intravitreal Ranibizumab or Triamcinolone Acetonide in Combination with Laser Photocoagulation for Diabetic Macular Edema - Ongoing study: enrollment complete

  • Intravitreal Ranibizumab or Triamcinolone Acetonide as Adjunctive Treatment to Panretinal Photocoagulation for Proliferative Diabetic Retinopathy - Ongoing study: enrollment complete

Age Related Eye Disease Study 2 (AREDS2):
This is a NEI-sponsored Phase III study designed to assess the effects of oral supplements of high doses of macular xanthophylls (lutein and zeaxanthin) and omega-3 LCPUFAs (DHA & EPA) for the treatment of age-related macular degeneration (AMD) and the development of advanced AMD. - Ongoing study: enrollment complete

Sponsor Website: www.nei.nih.gov
Principal Investigator: Sandeep Grover, M.D.
Co-Investigators: K.V.Chalam, M.D., Ph.D., Shailesh Gupta, M.D.

Industry Sponsored Clinical Trials

A Phase II Study of Implants of Encapsulated Human NTC-201 Cells Releasing Ciliary Neurotrophic Factor (CNTF) in Participants with Retinitis Pigmentosa:
This study evaluates the safety and effectiveness of Ciliary Neurotrophic Factor (CNTF) implants on visual function in people with retinitis pigmentosa. Status: Follow up - Complete - Closed

Sponsor: Neurotech USA
Principal Investigator: Sandeep Grover, M.D.

IRB sponsored department trials

To view our active trials sponsored by the Institutional Review Board, please visit our clinical trials page.

Translational Research

Aqueous humor analysis to assess ocular environment

Aqueous is intimately related to the cells of anterior and posterior chambers, which affect its composition. Aqueous analysis can provide useful information regarding physiological and pathophysiological processes in the eye. Using multiplex analysis we found that out of 90 analytes evaluated, 52 (57%) were detectable in the normal aqueous. To place these results in biological context, the functional pathways, networks, biological processes and disease processes these analytes represented were identified. Numbers of ocular pathology related processes were represented in aqueous. The detected analytes represented biomarkers of a number of relevant disease processes, including vascular diseases, arteriosclerosis, ischemia, necrosis and inflammation. To provide the proof of principle that aqueous profile could offer useful information about the pathophysiological processes, we analyzed 2 aqueous samples from diabetic patients. There were differences in normal and diabetic samples, including those relevant to diabetic retinopathy such as VEGF, C-reactive protein, glutathione and cytokines. Several biomarker groups for disease processes relevant to diabetes were perturbed. Moreover, ocular pathology/pathophysiology specific MAPs can be developed and used to analyze aqueous.

Implications of anti-VEGF therapy on ocular physiology and pathobiology

Vascular endothelial growth factor (VEGF) plays a key role in neovascularization by stimulating proliferation and migration of vascular endothelial cells. Anti-VEGF therapy, bevacizumab, acts by binding to VEGF and preventing its effects. However, this linear interaction represents only a partial view of pathobiology of neovascular diseases and the anti-VEGF treatment. To obtain an integrated view of the processes involved in ocular neovascularization we applied systems approach and investigated whether intravitreal bevacizumab injection had a global effect in normalizing the ocular physiology perturbed by the disease. Our results show intraocular bevacizumab injections changes the perturbed physiological environment of the eye towards normalization. Its effects reached beyond neutralizing VEGF. The results also demonstrate that large scale analysis of aqueous using systems approach could provide useful insight regarding ocular disease, their pathophysiology and treatment responses.

Although anti-VEGF therapy is widely used for ocular neovascular disorders, its safety has not been well studied. We looked at the safety profile of commonly used doses of bevacizumab on various retinal cells and found it to be safe.

Bevacizumab can also be potentially used for corneal neovascularization. Our studies show that bevacizumab is non toxic to corneal epithelium and the corneal fibroblasts in concentrations commonly used for ani-angiogenic purposes.

However, we found that bevacizumab may stimulate the proliferation nonspecifically by increasing the protein content of the cell growth environment. Results suggest that the typical amount of bevacizumab clinically injected into the vitreous can alter the internal milieu of the eye by increasing protein concentration that is sufficient to stimulate cell proliferation in certain cells. This might be especially relevant for cells not under VEGF control. Further studies are under way to determine if this could have any clinical implications.

Safety of use of various dyes in ocular surgery

Internal limiting membrane (ILM) peeling improves surgical outcomes in idiopathic macular hole, diabetic macular edema and epiretinal membrane. ILM, a thin transparent membrane is often difficult to visualize during vitreoretinal surgery and staining with vital dyes such as indocyanine green (ICG) improve visualization of the ILM intra operatively and facilitate its removal.

Recently, newer vital dyes have been proposed for staining internal limiting membrane, as an alternative to indocyanine green, which has been shown to be toxic to the retinal cells, in both in-vitro and clinical studies. Our experimental studies evaluated the comparative toxicities of new vital dyes - bromophenol blue, brilliant blue G and infracyanine green (IfCG) to establish a safe alternative to ICG.

In this in-vitro study, we report that among the 3 dyes tested, IfCG is the least toxic and a safe alternative to ICG for staining ICG during vitrectomy.

Basic Science Research

Effect of pathological ocular environment on ocular tissue

Oxidative stress is implicated in retinal ganglion cell (RGC) death in glaucoma. All the cells have elaborate defense mechanisms against oxidative stress. Our studies demonstrate that oxidative preconditioning can protect the RGCs from cytotoxic effects of lethal doses. This protective effect is probably mediated by NF-κB.

We also studied how ultraviolet light induced oxidative stress can cause degenerative changes by inducing pro-apoptotic protein Bax in retinal cells using retinal ganglion and retinal pigment epithelial cell cultures after various exposure time points.

In another study we looked at how the proliferative conditions of the retina, that are major causes of visual impairment, can produce factors that changes the intraocular environment in a way which is conducive for proliferation of other cells types, creating a vicious cycle. Our results demonstrate that proliferating retinotypic cells produce factors, including VEGF that can significantly alter the intraocular environment, such that it favors cell proliferation. These retinotypic cells have molecular machinery to produce and respond to VEGF. Breaking this cycle may provide an opportunity to modulate the course of proliferative vitreoretinal conditions.

Hypoxia is a pathological condition associated with a variety of ocular diseases including choroidal neovascularization. Our approach is to identify other factors other than VEGF which upregulates during neovascularization process. One of our in vitro research is underway to identify the different hypoxic factors and the associated transcriptional regulators and their expression in relation to choroidal neovascularization. This research will be helpful to identify the different epigenetic modulators involved in hypoxic conditions.

Effect of Proton beam radiation on ocular tissue

Neovascularization (newly sprouting endothelial cell) is a common complication associated with wet form of age-related macular degeneration. We are trying to utilize the new development of proton beam radiation, which has minimal entry and exit dose, for the treatment of neovascularization. Though some earlier clinical studies used this approach to treat neovascularization, none of the studies established a specific dosage. In our basic in vitro research using choroidal endothelial cells, we found that newly proliferating choroidal endothelial cells are sensitive between 8-12 CGE dosages of proton radiation. We also found that radiation-induced oxidative stress is a major cause of radiation induced sensitivity in choroidal endothelial cells. On the other hand, we are trying to establish the safety dosage to the retinal cells.

Further studies are underway to study the mechanistic or signaling pathways and the associated active proteins which are triggered by radiation and leading to apoptosis, necrosis and cell death. These in vitro results will provide a better insight for further in vivo experiments to proceed with this proton beam therapy from bench top to clinics.

Microbead fluoroanalyzer is more competitive to ELISA

Cytokines are involved in the pathology of wide range of diseases. Measurements of levels of cytokines are useful for understanding pathogenesis and as diagnostic and prognostic indicators in many diseases. The available gold standard technique for these markers is enzyme-linked immune sorbent assays (ELISA) which require large volume of sample. Eye is one of our systems where we can acquire small volume of sample such as aqueous humor.

In our studies, we determined that using microbead technology, which binds with protein of interest and produces fluorescent signal and measured using a fluoroanalyzer is a useful technology in comparison to ELISA at a lower volume of sample and at a lower concentration.

Research Faculty

Sankarathi Balaiya Mehanathan, Ph.D. [bio]

Kakarla V. Chalam, M.D., Ph.D., M.B.A., FACS [bio]
Professor

Sandeep Grover, M.D. [bio]
Associate Professor; Associate Chair, Department of Ophthalmology; Medical Director, Ophthalmology Trauma Service

Facilities

The research laboratory at the department of ophthalmology has modules for histology, molecular biology, cell culture, flow cytometry and microbead analysis. We have an outstanding collection of aqueous and vitreous samples from both normal and pathological eyes.

Histology facilities

We have human histological samples of different ocular pathologies and these samples are supplied from eye banks and from other institutions. Our lab has the expertise and is well equipped to perform immunohistochemistry experiments to identify the different protein expression and the results are analyzed using three channel and fluorescent microscopes (Olympus 1X51). Our investigators are experts with considerable experience in performing histological analysis including immunohistochemistry, confocal microscopy, electron microscopy and histochemical staining of both human and animal tissue.

Molecular biology facilities

We have very well equipped molecular biology facilities with gradient polymerase chain reaction cycler (PCR; Bio-rad) to amplify a specific gene from gene pool and western blot (Bio-rad) to visualize our protein of interest. PCR has a capability to do 8 different temperatures for 8 rows at one run and step-up, step-down and hot start PCR reactions. The amplified gene reaction products evaluated using either horizontal agarose gel electrophoresis unit or vertical polyacrylamide gel electrophoresis (PAGE) units whereas protein products were visualized using SDS-PAGE units. Further, the amplified gene products and immune blots can be quantified and analyzed using chemi-doc gel documentation system (Bio-rad).

Cytology

Our lab has a laminar flow hood under which we work on all cell work, in aseptic and contained environment, free of contamination. We have two CO2 incubators for preservation of cells and cell work. We also have a liquid nitrogen tank for storing our precious cells.

We quantify our cells using automated cell counter (Vi cell XR) which not only count our cells but also gives 50 camera images. This also tells our viable cell size in micron, circularity and the number of live and dead cell in each camera image and the average cell size and circularity for 50 camera images.

We use plate reader from Biotek synergy HT which is useful to measure luminescence, fluorescence and absorbance for functional, proliferative and cytotoxic experiments. We quantify reactive oxygen species concentration, DNA/RNA/protein concentration, protein interactions and cytokine levels using this plate reader. Instead of saying microplate reader we should say as ‘macro reader’ based on its usage.

Flow cytometry

We also have Quanta flow cytometer by Beckman Coulter for cellular analysis. This will also helpful to quantify the number of cells undergoing apoptosis and necrosis based on its specific fluorescent agent bound to cell. We use this instrument to identify the cells undergoing proliferative phase, resting phase in general cell cycle analysis in order to determine which phase cell cycle is affected by our treatment agent/condition.

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